“To answer the question of whether the improving economy might help people like Mr. Hampton and Ms. Barrington-Ward, economists often phrase the question as “Is it structural or cyclical?” Cyclical unemployment is temporary, caused by a slack economy. Structural unemployment stems from a mismatch between what businesses want and what workers offer. You are a car mechanic, for example, but the economy needs programmers.

If long-term joblessness is cyclical, a growing economy should bring people back into the job market. But if structural factors are at play, the concern is dire for the whole economy, with a normal unemployment rate “significantly higher than what has been achieved in the past,” said Janet L. Yellen, the presumptive new Federal Reserve chairwoman, in a speech this year.

Right now, most economists argue that unemployment remains primarily cyclical. Ben S. Bernanke, the departing Fed chairman, made this point last summer, adding that an unemployment rate in the 5 percent range — an indication of a healthy economy — was still obtainable. Growth simply hasn’t proved strong enough to spur businesses to hire all the people who want jobs.”